<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    .content {
      margin: 150px auto;
      width: 900px;
    }
  </style>
</head>
<body>
  <div id="app" class="content">
    {{a}}
  </div>
  <script src="../js/lib/vue.js"></script>
  <script src="../js/lib/art-template.js"></script>
  <script src="../js/lib/jquery-2.1.1.js"></script>
  <script>   
    var data = {a: '111'};
    var app = new Vue({
      el: "#app",
      data: data,
      created: function() {

        // this 指向app实例
        console.log("a is " + this.a);
      }
    });
    console.log(app.$data === data);
    console.log(app.$el == $('#app')[0]);

    app.$watch('a', function(newVal, oldVal) {
      console.log("newVal == " + newVal);
      console.log("oldVal == " + oldVal);
    });

  </script>
</body>
</html>